The first Tyrvaki colony to settle picked what they thought was a nice place. It was nice enough for the former human inhabitants, after all. Fresh water. Plenty of hunting opportunities. Fertile and arable land. Everything a settlement could desire.

And a nice population of subjugated natives to use as informants. These humans lived in an elevated structure they had made themselves, following the great plague. Well above the level of the land.

It took a few seasons to figure out why.

After the spring floods, which washed away half the colony and ruined the other half, came what the natives called gayturz in their guttural tongue. Giant lizards that camouflaged as driftwood, and could move like lightning in the abundant water.

Native humans ate them. And wore them. And used their bones and teeth as both decoration and tools.

But that wasn't the worst of it.

The rebuilding Tyrvaki colony was beset by another plague. They had drafted a native occupant with the barbaric native name of Klee-duss to assist with the engineering of new colony buildings on stilts.

Kal'rii ignored the human's advice to get indoors during the fading light. She dismissed it as typical male whining and a childish fear of the dark. Klee-duss also implored for the use of foul-smelling smokes and candles to keep away what Kal'rii imagined were fictitious foul spirits.

She also ignored Klee-duss adding layers to himself and smearing himself with foul potions. Typical ignorant native. They would learn to function under Tyrvaki rule or they would naturally die out.

As the artificial lighting came on, the whine began. Some small insect, no doubt. Annoying, but it could be ignored in favour of the surviving colony. No doubt, these tiny whining insects were the 'foul spirits' that had Klee-duss smacking himself in childish ignorance of the truth.

Kal'rii continued until the end of her shift, and retreated to the keeper-space she shared with Klee-duss, his surviving family, and -sadly- his foul potions against the bad spirits. Kal'rii slept in her breather mask that night.

And woke to devastation.

She was feeling unwell, and parts of her body itched where raised welts stretched her skin. The rest of the colony, especially the workers from the evening, was worse than unwell. Some were unrecognisable because of the proliferation of welts all over their bodies. Many had died. Many were near death.

"Tol' j'all t' get n'daws," slurred Klee-duss. He repeated himself as best he could in broken Tyrvakk. "I warn for inside. Many many."

"You know what caused this plague?" said Kal'rii.

"Yah. Skeeturz." He clapped one out of the air and showed her the smashed remains. Including the tiny smear of Tyrvakk blood still in its guts. "They gots d'zeaz in 'em. Plague blood go in guts."

2)

The second Tyrvaki colony, despite its own woes, sent a combat unit to investigate the sudden lack of communication from the first colony.

What they found in the ruins made for true horror. Proper Tyrvakk architecture was ruined or washed away by Terran flooding. Half-built hybrid architecture and temporary shelters alike were left abandoned to the invasive Kudzu plant.

And a little space away from the skeleton-infested ruins, a slightly larger human settlement contained the slim remains of the first colony.

Their leader, an engineer named Kal'rii, had gone both insane and native. She wore the gayturz skins and the foul potions that the natives of the Terran Naw'linz tribe used to ward off evil spirits. The few Tryvakk survivors had also adopted the natives' ways.

Their minds were clearly gone. They begged hysterically for the troops to join them in the elevated human buildings. Pleaded desperately for them to use the foul potions and gagging smokes. All while her human helper-pet quietly murmured to her in his barbaric, guttural tongue.

The troops, according to their logs, attempted to rebuild the colony buildings in a clear attempt to lure the mind-shattered colonists back to sensible technology and comfort. There were reports -unbelievable reports- of gigantic, flesh-eating lizards that sprang from the water and were gone with a Tyrvakk trooper in instants. And there were other reports of a high-pitched whine that travelled in the night air.

Those were the last reports of Tyrvakk infantry unit 547. Scout drones later investigated to find that every last soldier had perished.

The human assistants for Colony Two were unhelpful. They suggested, in broken Tyrvakk, that perhaps the efforts at colonisation were cursed. But of course the Tyrvaki were from the most advanced and rational of civilisations, and were immune to that superstitious nonsense.